South Dakota's foster care system "systematically violated the spirit and the letter" of a law meant to protect Native American children, a coalition of tribal directors from the state's nine Sioux tribes said in a report released Thursday night. The report comes a year after NPR aired a series questioning whether the law was being enforced.

The 30-year-old Indian Child Welfare Act says native children must be placed with relatives or their tribes if they are removed from their homes, except in unusual circumstances. The coalition said the state appears to have violated the law willfully, "and it may have done so at least partly to bring federal tax dollars into the state."

An official with South Dakota's Department of Social Services said in a statement that the department has not seen the report and cannot comment on it. They have said in the past they believe in the law and money has never influenced their program.

The group plans to send the report to Congress and is pushing lawmakers to force the Bureau of Indian Affairs to hold a promised summit to look into the issue. So far the BIA has failed to hold that summit. The BIA did not respond to requests for comment.

Update at 7:37 p.m. ET. 'Reviewing... Pressing Matters':

The BIA sent us this statement:

"Assistant Secretary for Indian Affairs Kevin Washburn was confirmed on October 6, 2012 and is diligently reviewing a number of pressing matters affecting tribes across Indian Country. He understands the critical nature of these particular issues and the tremendous importance of protecting the welfare of Indian children."